Structural and ultrastructural study of rat liver influenced by electromagnetic radiation.

Mobile communication systems are undoubtedly an environmental source of electromagnetic radiation (EMR). There is an increasing concern regarding the interactions of EMR with the humans. The aim of this study was to examine the effects of EMR on Wistar rat liver. Mature rats were exposed to electromagnetic field of frequency 2.45 GHz and mean power density of 2.8 mW/cm2 for 3 h/d for 3 wk. Samples of the liver were obtained 3 h after the last irradiation and processed histologically for light and transmission electron microscopy. Data demonstrated the presence of moderate hyperemia, dilatation of liver sinusoids, and small inflammatory foci in the center of liver lobules. Structure of hepatocytes was not altered and all described changes were classified as moderate. Electron microscopy of hepatocytes revealed vesicles of different sizes and shapes, lipid droplets, and proliferation of smooth endoplasmic reticulum. Occasionally necrotizing hepatocytes were observed. Our observations demonstrate that EMR exposure produced adverse effects on rat liver.

The alteration of glutathione peroxidase activity in rat organs after lead exposure.

The activity response of the antioxidant enzymes glutathione peroxidase (GPx), glutathione reductase (GR) and the contents of thiobarbituric reactive substances (TBARS) were investigated in rats exposed to lead. The enzyme activities were determined in the liver, kidney and heart of male and female rats which were received 100 mg and 1000 mg of lead acetate per liter water for 18 weeks. The statistical analyses indicated the differences related to the organs and to the sex of animals. Administration of lead evoked decrease of GPx activity in the kidney of both male and female rats. On the contrary, GPx activity increased in the heart of female rats, while in the male rats the higher dose of lead evoked a decrease in activity. In the kidneys of male rats and in the heart of female rats thiobarbituric acid reactive substances (TBARS), an indicators of oxidative stress, significantly increased in rats which were given the high lead dose. Most likely the observed changes could be a compensatory response to different lead accumulation in the male and female organs and also the possible distinct mechanisms in ROS elimination.

Are ruminal bacteria protected against environmental stress by plant antioxidants?

AIMS: To investigate the activity response of the antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GSHPx) of the rumen bacterium Streptococcus bovis following exposure to mercury(II) chloride (HgCl(2) in the presence of plant antioxidants. METHODS AND RESULTS: Streptococcus bovis was grown with 0 or 5 microg ml(-1) of HgCl(2) alone or together with antioxidant substances (AOS): seleno-l-methionine (Se), alpha-tocopherol (alpha toc), beta-carotene (beta car), melatonin (mel). The activities of SOD and GHPx were estimated in supernatants of disrupted bacterial cells. A significant decrease in the Strep. bovis SOD activity in the presence of HgCl(2) and tested AOS, except mel, was observed. The GSHPx activity of Strep. bovis was under the same cultivation conditions nonsignificantly changed and a significant decrease in the GSHPx activity was recorded only in the presence of beta car. CONCLUSIONS: The positive effect of Se, alpha toc and beta car on the elimination of environmental stress, evoked by mercury, in ruminal bacterium Strep. bovis in vitro was documented. SIGNIFICANCE AND IMPACT OF THE STUDY: The potential role of plant antioxidants in elimination of the environmental stress of ruminal bacteria evoked by heavy metals is discussed.

Antioxidant and detoxifying enzymes in the liver and kidney of pheasants after intoxication by herbicides MCPA and ANITEN I.

The activity of antioxidant and detoxifying enzymes, such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSHPx), glutathione reductase, glutathione-S-transferase (GST), the contents of thiobarbituric acid reactive substances, and the superoxide dismutase and glutathione-S-transferase isoenzyme patterns, were determined in the liver and kidney of pheasants after acute intoxication by herbicides MCPA and ANITEN I. In the liver, the activity of antioxidant enzymes was significantly decreased in the group given ANITEN I. New superoxide dismutase isoforms (pI 6.30, 6.85, 7.00) and higher intensity of isoform with pI 6.60 were observed after isoelectrofocusing in all experimental groups. In the kidney, the activity of superoxide dismutase was significantly decreased, and a higher intensity of superoxide dismutase isoforms (pI 6.00 and 6.60) was observed in all experimental groups. The contents of thiobarbituric acid reactive substances were significantly increased in the group with ANITEN I. The glutathione-S-transferase isoenzyme pattern was studied by using subunit-specific substrates and by Western blotting. The activity of glutathione-S-transferase with ethacrynic acid and cross-reactivity with rat subunit 7 was lower in all experimental groups in the kidney and liver, except in the liver of the group given a higher dose of ANITEN I. In this group, we have found a 2.10-fold higher activity to ethacrynic acid and a strong induction of subunit 7.

Antioxidant and detoxifying fish enzymes as biomarkers of river pollution.

The activity of several antioxidant and detoxifying enzymes, superoxide dismutase SOD, GSH peroxidase GSHPx, GSSG reductase GSR and GSH S transferase GST, the contents of thiobarbituric acid reactive substances TBARS, and the SOD and GST isoenzyme patterns were studied in the livers of chubs Leuciscus cephalus from reference river areas and polluted urban sites. Livers of polluted fish contained higher concentrations of transition metals, especially copper and iron. Total GSHPx activity was 1.8 fold higher in the polluted fish than in reference animals, while the SOD and GSR activities and the TBARS content were not significantly changed. Three new SOD isoforms pI 4.45, 5.1, 5.2 and a higher intensity of the band pI 4.2 were observed after isoelectrofocusing of polluted fish extracts. Total GST activity was higher in fish from polluted areas. The GST isoenzyme pattern was studied using subunit specific substrates DCNB, EPNP, EA, NPB, NBC and by Western blot using antibodies specific to rat GST subunits 1, 8 Alpha class, 3 Mu class and 7 Pi class. Reference and polluted fish lacked cross reactivity towards Alpha class GSTs. Reference fish displayed weaker cross reactivity towards CST 7 and 2.3 fold lower activity with EA, while higher cross reaction with GST 3 was observed in polluted fish.

Changes in GST-isoenzyme pattern of some organs of sheep exposed to different levels of pollution.

GST isonzyme patterns were studied in the cytosolic fraction of liver, kidney and lung of sheep exposed to industrial metal pollutants and compared with those of control animals. The methodology included the determination of enzymatic activities with several subunit-specific substrates (DCNB, NPB, EPNP and EA) and Western blotting using antibodies to specific rat GST subunits 1, 8 (alpha class), 3 (mu class) and 7 (pi class). In liver and lung, crossed reactivities with subunits 1 and 3 were absent in the controls but were present in exposed animals. Just the opposite result was obtained for subunit 8 crossed reactivity that was only in the control animals. In the kidney, crossed reactivities towards subunits 3 and 8 were absent and crossed reactivity equivalent to subunit 7 was present in all animals, and equivalent to subunit 1 was weakly induced in exposed animals. A 3.3-fold increase in the activity with NPB detected in the kidneys of exposed animals points to the induction of a theta class isoenzymes. Clear increases were found in the livers of exposed animals in the activities with CDNB (1.8-fold), DCNB (2.6-fold) and EPNP (2.1-fold), but no differences were found in the lungs with any of the substrates. The GST isoenzyme pattern of liver and lung could be, in principle, a useful biomarker of exposure to environmental pollution in sheep.

[The characteristics and regulation of glutamate dehydrogenase in strains of Bacteroides ruminicola ssp. ruminicola isolated from the rumen of fallow deer]. / Vlastnosti a regulácia glutamátdehydrogenázy izolovanej z bachora kmena Bacteroides ruminicola ssp. ruminicola u daniela.

Very little information about NH4+ assimilation paths in rumen anaerobic bacteria is available, and the information about wild animals is completely missing. Glutamate dehydrogenase (GDH) isolated from the rumen strain B. ruminicola in fallow deer was purified and its properties were specified after crystalline ammonium sulphate precipitation and gel filtration on Sephadex G-200. The properties of partly purified GDH were specified. One of the first specifications concerning GDH from various sources was to determine its coenzyme specificity. The results of these determinations enabled to draw a general conclusion that GDH from non-animal sources was specific to only one coenzyme while GDH from animal sources could utilize the two coenzymes (Frieden, 1964). In our study the specificity of GDH isolated from the rumen strain B. ruminicola in fallow deer to the coenzyme NADH (Tab. I) was determined; this specificity was different from the coenzyme specificity of GDH isolated from the rumen strain B. ruminicola in calves where GDH was found to be specific to the coenzyme NADPH. The effect of increasing concentrations of NADH, 2-oxoglutarate and NH4+ on the enzyme reaction velocity was also investigated and Km was determined for NADH, 2-oxoglutarate and NH4+ (Tab. II). The kinetic properties of GDH isolated from different sources are considerably variable. Michaelis constants for GDH range from 0.003 to 0.125 mmol/dm3 for NADPH (NADH), from 0.95 to 7.4 mmol/dm3 for 2-oxoglutarate, and from 0.25 to 16 mmol/dm3 for NH4+ (Misono et al., 1985). The average value of Km for NH4+ in a mixed rumen population was 33 mmol/dm3 (Erfle et al., 1977).(ABSTRACT TRUNCATED AT 250 WORDS)

[Glutamate dehydrogenase and glutamine synthetase activity in the digestive tract in lambs in relation to age]. / Aktivita glutamátdehydrogenázy a glutamínsyntetázy v tráviacom aparáte jehniat vo vztahu k veku.

Developmental dynamics was investigated in the activity of glutamate dehydrogenase (GDH, E.C. 1.4.1.2.-4) and glutamine synthetase (GS, E.C. 6.3.1.2) in different parts of the digestive tract of lambs, in dependence on the age from 10 to 90 days; the goal of these investigations was to elucidate in greater detail the role of the above enzymes in nitrogen metabolism. The activity of GDH, and of the coenzymes NADH and NADPH, was followed in the digesta because simple organisms (bacteria, fungi, plants) have two glutamate dehydrogenases: they differ from each other by coenzyme specificity, unlike GDH from animal sources which can utilize both NADH coenzyme and NADPH coenzyme (Fahien et al., 1965; Frieden, 1964). The following activities of GDH and GS were found out in trials with lambs at the age of 10, 20, 30, 40 and 90 days, as to the different parts of digestive tract: in the tissues of rumen, omasum, reticulum, spleen, duodenum, jejunum, ileum, int. caecum and colon the activity of GDH (NADH) varied from 0.031 to 0.305 nkat/mg dry matter, in the digesta from 0 to 2.92 nkat/mg dry matter. An investigation of GDH (NADH, NADPH) dynamics in the digesta of lambs showed the relatively high activity of GDH (NADH) in the digesta of colon at the age of 10 days and that of GDH (NADPH) in the digesta of int. caecum. The activity of GDH (NADH) was also found to be high in the digesta of int. caecum at the age of 20 days. In that period the activity of GDH (NADH, NADPH) in the digesta of rumen, omasum and reticulum was zero.(ABSTRACT TRUNCATED AT 250 WORDS)

Glutamate dehydrogenase and glutamine synthetase activity of the bacteria of the sheep's rumen after different nitrogen intake.

In experiments on 18 sheep with a differentiated nitrogen intake (3.7, 6.2 and 21 g N/day), it was found that different enzyme activities--glutamate dehydrogenase (GDH) (NADH- and NADPH-dependent) and glutamine synthetase (GS)--of bacteria adhering to the rumen wall and to food particles and the rumen fluid bacteria altered in correlation to the nitrogen intake. With a nitrogen intake of 3.7-6.2 g/day there was a significant increase, and of 6.2-21 g/day a decrease, in NADH- and NADPH-dependent GDH activity in the three given bacterial fractions, with the exception of NADPH-dependent GDH activity of the rumen fluid bacteria of sheep given 3.7-6.2 g N/day, in which the difference was nonsignificant. GS activity was significantly higher only in adherent rumen wall bacteria in the presence of a nitrogen intake of 3.7-6.2-21 g/day. The results show that the effect of the nitrogen intake on the given enzyme activities is strongest in the case of bacteria adhering to the rumen wall. The high GS activity and low GDH activities in these bacteria during lower nitrogen intakes (3.7 g/day) as well as lower rumen ammonia concentration (2.39 +/- 0.98 mmol.l-1) indicate that bacteria adhering to the rumen wall utilize ammonia at an increased rate by means of CS catalyzed reactions. Reduced GDH activity in the presence of a high nitrogen intake (21 g/day) and the relatively high rumen ammonia concentration (36.63 +/- 5.28 mmol.l-1) indicate that ammonia inhibits this enzyme in the rumen bacteria in question.

Ammonia-utilizing enzymes of adherent bacteria in the sheep's rumen.

In experiments on 6 sheep the authors found the following enzyme activities in bacteria in the rumen fluid, bacteria adhering to the epithelium of the rumen wall and bacteria adhering to food particles in the rumen (given in nkat X g-1 bacterial dry weight): GDH (NADH): 725 +/- 165, 558 +/- 127, 661 +/- 153; GDH (NADPH): 558 +/- 338, 255 +/- 88, 565 +/- 139; GOAT (NADH): 46 +/- 23, 67 +/- 31, 66 +/- 14; GOGAT/NADPH: 58 +/- 27, 56 +/- 15, 65 +/- 29; GS: 153 +/- 65, 69 +/- 35, 71 +/- 32; ALT: 71 +/- 25, 43 +/- 20, 52 +/- 11; AST: 52 +/- 12, 33 +/- 16, 28 +/- 15. The results show that, except for GDH (NADPH), there were no significant differences between the given enzyme activities in the rumen fluid and in bacteria adhering to the rumen wall and to food. Adherent rumen bacteria have the same potential possibilities as the rumen fluid bacteria for the utilization of ammonia, particularly for the synthesis of glutamic acid, glutamine, alanine and aspartic acid, with the above enzymes as catalysts. By means of the GS/GOGAT system, adherent rumen bacteria can probably synthesize glutamic acid in the presence of a limited NH3 concentration in the rumen.

Origin of glutamate dehydrogenase from the mucosa of the sheep rumen.

Glutamate dehydrogenase [GDH] from the mucosa of sheep rumen was partly purified and characterized. In chromatography on DEAE cellulose, GDH activity separated into two fractions. Fraction I, isolated at a low NaCl gradient concentration, was not affected by Zn2+ or by the purine nucleotides GTP and AMP. The chromatographic behaviour of fraction II was the same as the parallel fraction isolated from the liver by the same technique. The activity of fraction II and the liver fraction was strongly inhibited by Zn2+ in 10(-6) to 3.10(-5) mol/1 concentration and by GTP in 10(-5) to 2.10(-5) mol/1 concentration. It was activated by AMP in 5.10(-6) to 6.10(-5) mol/1 concentration and by leucine in 3.10(-3) to 10(-2) mol/1 concentration. The coenzyme specificity of fraction I was greater for NADPH than for NADH. In the case of fraction II, like the fraction isolated from sleep liver, it was greater for NADH than for NADPH. It is concluded from the different effect of Zn2+ and of purine nucleotides on the enzyme activity of the fractions isolated from rumen mucosa that the mucosa of the sheep rumen contains two enzymes with GDH activity, one of which [probably adsorbed] is of bacterial origin and the other is a constitutive tissue enzyme of the rumen wall.

[The effect of feeding rumen contents on glutamate dehydrogenase activity in some organs of broilers]. / Vplyv skrmovania bachorového obsahu na aktivitu glutamátdehydrogenázy v niektorých orgánoch brojlerov.

The effect of the replacement of 50, 60 and 80% of proteins in diet by dried rumen contents on glutamate dehydrogeanse activity (EC 1.4.1.3) in the kidneys, liver, and caecum tissue and contents was studied in broilers. The liver and caecum tissue did not show any significant changes in the activity of glutamate dehydrogenase (GLDH) in dependence on the concentration of rumen contents in the diet. A statistically significant drop of GLDH activity was ascertained in the kidneys, the drop being the most marked at a 65% concentration of rumen contents in the diet. Similarly, a statistically significant decrease of GLDH activity, caused by rumen contents feeding in comparison with the control, was observed in caecum contents, in which the activity of GLDH was the highest.

Distribution of glutamate dehydrogenase and glutamine synthetase activity in the sheep and chicken digestive tract.

Glutamate dehydrogenase (GLDH, EC 1.4.1.3) and glutamine synthetase (GS, EC 6.3.1.2) activity were determined in the contents and tissues of the various parts of the sheep and chicken digestive tract, GLDH activity in the tissues of the sheep omasum, duodenum, rumen, reticulum, colon, caecum, jejunum and ileum ranged from 3.25+/-0.7 U (mumol/g dry weight . min) to 5.94+/-2.28 U; in the abomasum it was 9.67+/-1.27 U. GLDH activity in the contents of the ileum, abomasum, jejunum and duodenum varied from 0.85+/-0.19 U to 3.29+/-0.53 U and in the colon, caecum, reticulum, omasum and rumen from 6.34+/-2.64 U to 16.96+/-3.83 U. GS activity in the tissues of these parts of the digestive tract varied from 2.8+/-0.59 U to 8.6+/-1.4 U and their contents from 2.49+/-0.85 U to 10.76+/-2 U. GS activity in the contents of the colon was very low (0.26+/-0.07 U). In the tissues of the chicken duodenum, caecum, jejunum and ileum we found GLDH activity of 4.68+/-1.64 U to 7.96+/-1.73 U; in their contents it was 3.31+/-1.06 U to 3.8+/-0.73, but in the caecum it attained up to 66.7+/-24.3 U. GS activity was high from 57.6+/-2.0 U to 231+/-84 U in the tissues and 357+/-53 U to 383+/-76 U in the contents (in the caecum up to 2,500+/-233 U). The results show that conditions for the utilization of ammonia are present in the tissues and the contents in the whole of the sheep and chicken digestive apparatus. The hypothesis is confirmed that the different ability of ruminants and fowls to utilize ammonia formed from urea added to their feed, including ammonia formed by hydrolysis of blood urea, is due to the different GLDH and GS activity in their digestive tract as well as in their liver.

[Effect of dietary nitrogen compounds and urea on the GLDH and DS activities in broilers]. / Vplyv koncentrácie dusíkatých látok a mocoviny v diéte na aktivitu gldh a gs u brojlerov.

The influence of concentration of nitrogenous matters (N-matters) and urea supplement in diet for broilers was studied, as exerted on the activities of the enzymes glutamate dehydrogenase (GLDH) and glutamine synthetase (GS) in liver, kidney, tissue and contents of the cecum. If 2% urea had been substituted for a portion of N-matters, no significant differences in the activities of both enzymes in liver and cecum were found. Higher levels of GLDH were recorded in the kidney of broilers given diets with the urea supplement of 17 and 19% N-matters concentrations. The GLDH and GS activities were significantly high in the contents of the cecum, the GLDH activity being the highest with the diet of 19% N-matters concentration. No significant changes in the GLDH activity depending on the concentration of N-matters in the diet were observed in the liver. The GS activity increased moderately with the higher concentration of N-matters.

Glutamate dehydrogenase and glutamine synthetase activity in some organs of ruminants and monogastric animals.

A comparative study of glutamate dehydrogenase (GLDH 1.4.1.2) and glutamine synthetase (GS 6.3.1.2.) activity in liver, kidney and spleen homogenates from cattle, sheep, pigs and chickens showed that chicken liver contained on an average 3.5%, pig liver 8.3% and bovine liver 45.6% of the glutamate dehydrogenase activity present in sheep liver. Relatively low trace activity was found in the spleen and kidneys, except for the renal cortex of cattle (32% of activity in the liver). GS activity was the highest in chicken liver; in pigs it amounted to 33.40%, in cattle to 24.2% and in sheep to 19.7% of this activity. No marked interspecies differences were found in the values in the kidneys and spleen. It can be concluded from the results that the relatively high GLDH activity in the liver of ruminants compared with pigs and chicken is associated with the greater ability of ruminants to utilize ammonia. The higher GS activity and lower GLDH activity in chicken liver can be attributed to higher uric acid synthesis from ammonia via glutamine and purine bases and the lower ability of birds to utilize ammonia for protein synthesis. The presence of alanine dehydrogenase was not demonstrated in chicken liver, where the maximum oxidation of NADH after the addition to pyruvate and ammonia substrate was found.

[Effect of a urea diet on glutamate dehydrogenase and glutamine synthetase activity in various organs of chickens]. / Vplyv mocovinovej diety na aktivitu glutamátdehydrogenázy a glutaminsyntetazy v niektorých orgánoch brojlerov

The total values were determined for the activity of glutamate dehydrogenase, glutamine synthetase, and dehydrogenase with pyruvate in broilers fed a diet with a 0, 2 and 4% content of urea for three weeks. A statistically significant increase of glutamate dehydrogenase activity was ascertained in the liver and kidney of broilers. The increase of the activity of glutamine synthetase in liver was close to the threshold of statistical significance. Dehydrogenase activity with pyruvate increased in liver.